Scoop-trimmed fluid couplings

ABSTRACT

The trimming scoop of a scoop-trimmed fluid coupling is interconnected with a movable weir tube in an overhead reservoir to effect complementary changes in the volumes of liquid in the reservoir and the working circuit or circuits of the coupling on movement of the weir tube and scoop tube in either direction. A cooling flow path may extend from the reservoir to the working circuit or circuits.

O Umted States Patent 1 [111 3,733,821 Bilton [451 May 22, 1973SCOOP-TRIMMED FLUID COUPLINGS [56] References Cited [75] Inventor: JohnBilton, Hampton, England UNITED STATES PATENTS 3 Assignee: FluidriveEngineering Company gepger e en gagg Islewmh' M'ddlesex En 3,581,5026/1971 Thylefois ..60/54 [22] Filed: Sept. 22, 1971 PrimaryExaminer-Edgar W. Geogliegan 1 pp No 182 624 Attorney-Woodhams,Blanchard and Flynn [57] ABSTRACT [30] Foreign Application Priority DataThe trimming scoop of a scoop-trimmed fluid coupling Sept. 24, 1970Great Britain ..45,599 70 is interconnected with a movable Weir tube inan Overhead reservoir to effect complementary changes in the [52] US. Cl60/351 volumes of liquid in the reservoir and the working Cir- 51 Int.Cl. .msu sa/id riil 41/04 circuits of the the [58] Field of Search 60/54weir tube and scoop tube in either direction. A coolg flow p y extendfrom the reservoir to the working circuit or circuits.

7 Claims, 5 Drawing Figures n m 55 46 T? J T"N L \E 4 2 [2 3 32 ,5

5, 7 9 1o 8 I I I 23"? 52 m :7 i? 162422 J PATENTEL rs-x22 m5 SHEET 1 BF3 SCOOP-TRIMMED FLUID COUPLINGS This invention relates to scoop trimmedfluid couplings, that is to say fluid couplings in which a casingrotates with one of the two vaned elements which together define a.toroidal working circuit for liquid and an adjustable trimming scoopextends into a scoop chamber formed within the casing to trim off liquidfrom this chamber and thereby control the quantity of liquid within theworking circuit.

In operation, working liquid is supplied continuously to the workingcircuit at a constant rate, typically by a filling pump. In the steadystate corresponding to any particular position of the trimming scoop,working liquid is removed by the scoop at the same rate as it issupplied by the pump.

While this arrangement enables a cooling circulation to be maintainedthrough the coupling, the need for a continuously running pump increasesthe initial cost and the mechanical complexity. Further, the maximumfilling flow rate available is limited to the delivery rate of the pump.Thus, to increasethe filling rate a larger pump has to be used therebyincreasing the initial cost and absorbing more power in maintaining alargerthan-necessary flow through the coupling.

In US. Pat. No. 3,521,451, the working liquid is water and the pump isomitted. Instead, a continuous flow (corresponding to the pump delivery)is passed through the coupling from a mains supply to a drain. While theinitial cost is reduced, this arrangement is not suitable for manyapplications, such as underground conveyor belt drives in mines.Moreover, the higher the filling rate required, the higher is thecontinuous flow from mains to drain during normal running.

It has been proposed in British Pat. No. 328,028 to use a reservoirconnected to deliver working liquid under a pressure head, for example agravitational head, to the working circuit. The degree of filling of theworking circuit is controlled by adjusting the outlet flow from thereservoir to the coupling, the scoop being fixed with its scoop orificepermanently at the circuit empty position, that is at the same radialdistance from the coupling axis as the radially outermost portion of theworking circuit. While this arrangement enables the required flow rateto the working circuit to be obtained the scooping orifice mustnecessarily be in the position where it exerts the maximum drag torqueon the coupling under all conditions. Further, to obtain an acceptableemptying time for discontinuing drive through the coupling, the scoopmust continuously withdraw liquid from the working circuit at the emptyrate even under normal driving conditions. This again results in ahigher circulation rate than may be required for cooling and aconsequent waste of power.

According to the present invention there is provided a scoop trimmedfluid coupling assembly characterized in that it includes a stationaryreservoir arranged to deliver working liquid under a filling pressurehead to the working circuit and means for controlling the delivery ratefrom the reservoir to the working circuit and in that the control meansis interconnected for movement with the scoop. tube in such a manner asto deliver a larger flow rate to the working circuit when the scoopingorifice of the scoop tube moves out of the scoop chamber to fill theworking circuit than during the steady state.

Conveniently, the reservoir extends above the level of the workingcircuit and a movable weir tube communicating with the scoop tube has amovable weir orifice within the reservoir and is interconnected formovement with the scoop tube in such a manner that as the scoopingorifice of the scoop tube moves into the scoop chamber to empty theworking circuit, the weir orifice rises within the reservoir and theliquid trimmed off from the scoop chamber is discharged through the weirorifice into the reservoir whereas when the trimming scoop orifice iswithdrawn to its circuit full position, the weir orifice moves below thelevel of liquid in the reservoir and liquid flows back through the weirorifice from the reservoir into the scoop chamber to refill the workingcircuit. If desired a continual flow of cooling liquid can be maintainedthrough the working circuit of the coupling by providing a flow pathfrom the reservoir to a point near the axis of the coupling from whichliquid can enter the redially inner part of the working circuit, theresultant excess of liquid in the working circuit being trimmed off bythe scoop and being returned through the weir tube and weir orifice tothe reservoir.

Particularly where it is desired that the coupling should be suitablefor either direction of rotation, the scoop tube may be a double scooptube having separate orifices facing in opposite directions and eachorifice may be connected to its own weir tube working in a commonreservoir. With this arrangement, the cooling flow may also be obtainedby direct collection of liquid by a scooping orifice facing in theforward direction, the liquid thus collected flowing into the reservoirby the weir tube connected to the forwardly facing scoop orifice andthereafter returning to the working circuit through the other weir tubewhich communicates with the rearwardly facing scoop orifice.

The scoop tube may be of the arcuate form shown in German Pat. No.'820,660 mounted for pivotal movement about a horizontal axis transverseto the coupling axis and displaced therefrom. With such an arrangement,the scoop tube may be carried by a hollow shaft which also carries theweir tube or tubes. The scoop tube, hollow shaft and weir tube-or tubesthen move as a single unit about the transverse axis, the interior ofthe scoop tube being connected with the weir tube through the interiorof the hollow shaft.

In an alternative arrangement, the scoop tube is of the well-knownsliding type and the weir tube is pivotally mounted and has an extensionbeyond its pivotal mounting, the extension being articulated to thescoop tube. A connection for flow of liquid from the scoop tube to theweir tube is provided. This may conveniently be effected through thearticulation joint between the scoop tube and the weir tube.

Embodiments of the invention will now be described by way of examplewith reference to the accompanying drawings, in which FIG. 1 shows inaxial section the upper half of a scoop trimmed coupling incorporatingthe invention,

FIG. 2 is a section on the line IlllII of FIG. 1,

FIG. 3 is an axial sectional view of the upper half of 7 anotherembodiment of the invention in the form of a mounted in bearings 3 in ahousing 4 for the coupling.

Twin working circuits 5 and 6 are defined by vaned impeller elements 7and 8 and runner elements 9 and 10. The impeller element 7 is bolted at11 to a flange on the input shaft 1 and a cylindrical casing portion 12interconnects the outer peripheries of the two impeller elements 7 and8. A scoop chamber casing portion 13 is also secured to the outerperiphery of the impeller 8.

The two runner elements 9 and are secured together back-to-back byrivets 14 and are bolted at 15 to a flange 16 and an output shaft 17mounted in a bearing 18 in the housing 4. The output shaft 17 may have aspigot 19 received in a bearing within the end of the input shaft 1.

The hub of the impeller 8 is bolted to a flange 21 of a sleeve 22 whichis journalled at 23 in a bearing carried by an inwardly extendingcylindrical portion 25 of the housing. Thus, input stub shaft 1,impeller 7, casing 12, impeller 8 and sleeve 22 comprise a rigidrotating bridge. This bridge is supported between journal bearing 3 andsleeve bearing 24. In place of the spigot 19, the output shaft 17 may besupported by a split bearing bush 24 carried by the sleeve 22 whichwould then be formed with feed holes if working liquid is to be suppliedto the working circuit from within the sleeve 22.

The scoop chamber portion 13 of the rotating casing of the coupling hasits end wall 26 shaped to conform to the movement of an arcuate scooptube 27 mounted on a hollow shaft 28 supported in bearings 29 (FIG. 2)in the housing 4. The scoop tube 27 has two orifices 31 and 32 openingwithin the scoop chamber formed by the casing member 13. The angularposition of the shaft 28 and thus the radial position of the scoop tubeorifices 31 and 32 may be adjusted by any appropriate means such as thelever 33 shown in FIG. 2 or a servocontrol device (not shown).

In the construction shown in FIG. 2, the hollow shaft is in the form ofthree separate portions: a central portion 33 integral with the scooptube 27 and two outer portions 34 and 35. The center portion 33 isdivided internally by a wall and its ends are shaped to interfit withthe adjacent ends of the two outer portions 34 and 35 so as to provide arotational driving engagement while permitting slight angularmisalignment between the portions of the hollow shaft 28. The orifice 31communicates with the outer portion 34 and the orifice 32 with the outerportion 35. O-ring seals 36 prevent leakage of working liquid throughthe support bearings 29.

Each of the outer portions 34 and 35 of the hollow shaft 28 carries anelbowed weir tube 37 and 38 respectively. Each weir tube 37, 38 extendsinto a side pocket portion 39, 40 of a reservoir tank 41 defined in theupper part of the housing 4. The floor 42, 43 of the side pocketportions 39 and 40 at the input end of the housing 4 is higher than thefloor portions 44, 45 nearer the output end of the housing 4 in order toprovide clearance for the rotating coupling casing at the input end ofthe coupling and extends beneath the hollow shaft 28 adjacent the outputend of the coupling.

Each of the weir tubes 37 and 38 terminates in a weir orifice 48, 49which define the liquid level in the reservoir tank 41. If the lever 33is moved to lower the orifices 48, 49 below the liquid level in thereservoir tank 41, liquid will tend to flow under gravity through theweir tubes 37 and 38 into the hollow shaft 28 and from thence throughthe arcuate scoop tube 27 and whichever of the orifices 31 and 32 isfacing in the direction of movement of the scoop chamber casing 13 asthe latter rotates. In this way, the filling of the coupling isincreased.

If however the lever 33 is moved in the direction to raise the orifices48, 49 above the level of liquid in the reservoir tank 41, the scoopingorifices 31 and 32 will be plunged into the ring of liquid in the scoopchamber and accordingly liquid will be trimmed off by whichever of thescoop orifices 31, 32 is facing in the opposite direction to thedirection of movement of the casing member 13 and liquid will be forcedinto the scoop tube 27 and thence through the hollow shaft and theappropriate weir tube 37 or 38 into the reservoir tank 41.

In this way, it can be seen that no circulation pump is necessary forreplenishing or filling the working circuit.

The coupling shown in FIGS. 1 and 2 could be designed for use with wateror a water and oil emulsion as working liquid in which case the variousbearing bushes for supporting the shafts (e.g. the bushes 18, 23 and 24)could be of polytetrafluoroethylene. The double circuit arrangementavoids the need for any substantial axial thrust bearing.

If a flow of liquid for cooling the working circuits is required, thecoupling may include a pipe 51 to which the cooling liquid is supplied,the flow of which is controlled by a bleed screw 52 with a lock nut 53.The working'liquid passing the tapered head of the bleed screw 52 flowsthrough a passage 54 in the cylindrical housing portion 25, into theworking circuit 6 and thence into the interior of the casing 12, 13, thetank having an overflow outlet 55 for any accretion of liquid not lostby leakage through the normal labyrinth seals.

In an alternative arrangement, the cooling flow may be taken from thebottom of the tank 41, passed through an external cooler (not shown)andthen fed into the pipe 51 at a level lower than that of the overflowpipe 55. A shut-off valve would then be ganged with the lever 33 toclose pipe 51 in the circuit empty position to prevent the tank beingdrained.

The coupling shown in FIG. 3 differs from that described in FIGS. 1 and2 in that the coupling has a single working circuit W and the scoop tube61 is of the conventional sliding type which is here supported forsliding movement in a trunnion 80 mounted for angular movement in across bore in which it is retained by a circlip 81.

The input shaft 62 carries a casing 63 comprising a bell-shaped housing64 to which is secured a scoop chamber casing 65 and the impeller 66which together with a runner 67 defines the working circuit W. Therunner 67 is secured to an output shaft 68. One end of the output shaft68 is supported in a bearing 69 in the hub of the casing 63. The inputshaft 62 and output shaft 68 are both supported in bearings where theypass through the walls of a stationary housing 71 for the coupling. Areservoir tank 72 is formed in the upper part of the housing 71.

A weir tube 73 is carried by a horizontal hollow shaft 74 which passesout through a side wall of a pocket 75 of the reservoir tank 72 andcarries an extension 76 which is articulated to the scoop tube 61 bymeans of a joint 77 which permits flow of the working liquidtherethrough.

I claim:

l. A scoop-trimmed fluid coupling assembly comprising a fluid couplingin which a casing rotates with one of the two vaned elements whichtogether define a toroidal working circuit for liquid and an adjustabletrimming scoop extends into a scoop chamber formed within the casing totrim off liquid from this chamber and thereby control the quantity ofliquid within the working circuit, wherein the assembly includes astationary reservoir arranged to deliver working liquid under a fillingpressure head to the working circuit and means for controlling thedelivery rate from the reservoir to the working circuit and wherein thecontrolling means is interconnected for movement with the scoop tube insuch a manner as to deliver a larger flow rate to the working circuitwhen the scooping orifice of the scoop tube moves out of the scoopchamber to fill the working circuit than during the steady state.

2. A coupling assembly according to claim 1, wherein the reservoirextends above the level of the working circuit and a movable weir tubehas a movable weir orifice within the reservoir and is interconnectedfor movement with the scoop tube in such a manner that correspondingmovements of the scoop tube and weir orifice cause complementary changesin volume of working liquid in the coupling and the reservoir.

3. A coupling assembly according to claim 2, wherein the scoop tube isarcuate and is provided about an axis, and the weir tube is fixed to thescoop tube by a hollow shaft which provides liquid communicationbetween, and forms the pivotal axis for, the weir tube and scoop tube.

4. A coupling assembly according to claim 2, wherein the scoop tube isslidable and the outer end of the scoop tube is articulated to the weirtube.

5. A coupling assembly according to claim 4, wherein the articulationbetween the scoop tube and weir tube is hollow and provides liquidcommunication between the scoop tube and weir tube.

6. A coupling assembly according to claim 5, wherein the scoop tube isslidable in a pivot.

7. A coupling assembly according to claim 1, including means defining arestricted flow path for cooling liquid from the reservoir to thecoupling working circuit.

1. A scoop-trimmed fluid coupling assembly comprising a fluid couplingin which a casing rotates with one of the two vaned elements whichtogether define a toroidal working circuit for liquid and an adjustabletrimming scoop extends into a scoop chamber formed within the casing totrim off liquid from this chamber and thereby control the quantity ofliquid within the working circuit, wherein the assembly includes astationary reservoir arranged to deliver working liquid under a fillingpressure head to the working circuit and means for controlling thedelivery rate from the reservoir to the working circuit and wherein thecontrolling means is interconnected for movement with the scoop tube insuch a manner as to deliver a larger flow rate to the working circuitwhen the scooping orifice of the scoop tube moves out of the scoopchamber to fill the working circuit than during the steady state.
 2. Acoupling assembly according to claim 1, wherein the reservoir extendsabove the level of the working circuit and a movable weir tube has amovable weir orifice within the reservoir and is interconnected formovement with the scoop tube in such a manner that correspondingmovements of the scoop tube and weir orifice cause complementary changesin volume of working liquid in the coupling and the resErvoir.
 3. Acoupling assembly according to claim 2, wherein the scoop tube isarcuate and is provided about an axis, and the weir tube is fixed to thescoop tube by a hollow shaft which provides liquid communicationbetween, and forms the pivotal axis for, the weir tube and scoop tube.4. A coupling assembly according to claim 2, wherein the scoop tube isslidable and the outer end of the scoop tube is articulated to the weirtube.
 5. A coupling assembly according to claim 4, wherein thearticulation between the scoop tube and weir tube is hollow and providesliquid communication between the scoop tube and weir tube.
 6. A couplingassembly according to claim 5, wherein the scoop tube is slidable in apivot.
 7. A coupling assembly according to claim 1, including meansdefining a restricted flow path for cooling liquid from the reservoir tothe coupling working circuit.